Abstract: Spaces and elements in the built environment have emerged as platforms where materializations of observations and actuations promise to be very profitable. The advent of the Internet of Things (IoT) paves the way to address this challenge but the heterogeneity of the represented knowledge about these artifact systems poses a real problem. Ontologies can be considered as part of the solution to overcome the IoT’s inherent hurdles. A wise option promoted by recent approaches is to design networks of complementary ontologies. However, different points of view are possible and such diversity could lead to interoperability problems. This article advocates for a networked ontology infrastructure conceived on a principled basis guided by documented judicious conceptualizations. In this regard, this survey points towards ontologies involved in conceptualizations of observations and actuations, where the utility of that conceptualization arises when some features of interest need to be observed or acted upon. For each of the reviewed ontologies, their fundamentals are described, their potential advantages and shortcomings are highlighted, and the use cases where these ontologies have been used are indicated. Additionally, use case examples are annotated with different ontologies in order to illustrate their capabilities and showcase the differences between reviewed ontologies. Finally, this article tries to answer two research questions: Is there a firm basis, broadly admitted by the community, for the development of such a networked ontology infrastructure for the observations and actuations in buildings? What ontologies may be considered helpful towards that goal?